Conduct a comparative study of hemofiltration and hemodialysis in an A B A crossover design. A series of outcome measures will be taken over the control and experimental periods with the ojbective of determining the relative clinical response. Cost data will also be collected so that both clinical efficacy as well as treatment costs can be compared. The study will involve 12-14 patients in an A B A design of 3-6-3 month periods. Extensive outcome measures are to be recorded.